code: def test_metrics_show_default(capsys):
      show_metrics(
          metrics={
              "branch_1": {
                  "data": {
                      "metrics.json": {
                          "data": {"b": {"ad": 1, "bc": 2}, "c": 4}
                      }
                  },
                  "error": Exception("Failed just a little bit"),
              },
              "branch_2": {
                  "data": {
                      "metrics.json": {
                          "data": {"a": 1, "b": {"ad": 3, "bc": 4}}
                      }
                  }
              },
          },
          all_branches=True,
      )
      out, _ = capsys.readouterr()
      assert out == textwrap.dedent(
          """\
          Revision    Path          a    b.ad    b.bc    c
          branch_1    metrics.json  -    1       2       4
          branch_2    metrics.json  1    3       4       -
          """
      )
  
imports: import textwrap
  import pytest
  from dvc.compare import diff_table, metrics_table, show_diff, show_metrics
  from dvc.utils.serialize import YAMLFileCorruptedError
label_desc: Use image node_id 24 for calling a global function with example usage: test_metrics_show_default(capsys) without return types